Question

An antibiotic medicine has stopped working for some patients. Now you want to find out why. Write a short project plan how you approach this problem. It should contain examples of scientific questions you ask on the way to the goal, and after each question a brief description of the methods you apply. The method descriptions should indicate how the method works (what it does), what type of results it gives, and how the results would contribute to answering the question.

Answer 1

Excessive usage of antibiotics causes antibiotic resistance. A variant which is resistant to antibiotic gets selected more resulting in more offspring produced of its type. This results in complete wiping out of the susceptible ones and increase in the number of resistant ones. This is the reason why the antibiotics will no longer will be effective on a particular organism.

1. First question can be if there is any thing wrong with the batch of the medicine used. Expiry date of the medicine used. That can be very easily clarified.

2. If the medicine is working normally on other microbes if it is broad spectrum antibiotic. this can be verified by taking the culture plates with specific microbe and performing disc diffusion test. If the antibiotic is working on these microbes you will find zone of inhibition around the antibiotic disc. In such a case, we can consider that there is nothing wrong in the antibiotic as such.

3. Is there any resistance in the microbe to the antibiotic. This can be verified by the same disc diffusion test which is also called Kirby-Bauer test.

In disc diffusion test we take the culture plates with specific bacteria growing in them. Small wafers with the antibiotic are placed in the growing lawn of the bacteria. If the bacterial growth is restricted around the antibiotic disc (zone of inhibition ) , it tells about the susceptibility of the bacteria to antibiotic. If the bacterial are growing normally around the antibiotic disc, this indicates the resistance of the bacteria to that particular antibiotic.